Hot gas engine

ABSTRACT

A hot gas engine construction employing either external combustion, internal combustion, or a combination of both internal and external combustion. The engine has a fresh air or gas intake means connected to a casing with a motor connected to the opposite end of the casing, and a chamber in the casing having heat supplied thereto by either heat exchangers or by internal ignition of combustionable fluids thereby effecting the expansion of the gas and the increase of the pressure in the chamber between the intake means and the motor means. This forces the heated gases out of the chamber through the motor effecting the driving of the motor which has its output connected through suitable means to a load to be driven along with being drivingly connected to the intake means for effecting the operation of the same to introduce fresh air or gas into the chamber.

Unite Roblyer States tet m1 1 Augfll i973 HOT GAS ENGINE [22] Filed:Dec; 9, 11971 [21] Appl. No.1 206,246

[52] [1.8. Ci. 60/24, 60/59 T [51 int. Cl. F02g 1/04 [58] Field ofSearch 60/36, 592, 59 T [56] References Cited UNITED STATES PATENTS2,685,173 8/1954 Percival 60/59 R 3,022,235 2/1962 Brown 60/105 XFOREIGN PATENTS OR APPLICATIONS 13,206 9/1888 Great Britain 60/24 18,6659/1905 Great Britain 60/24 OTHER PUBLICATIONS Ford Motor CompanyAdvertising Circular, May 1956.

Primary Examiner-Martin P. Schwadron Assistant Examiner-Allen M.Ostrager Attorney-George F. Dvorak et al.

[57] ABSTRACT A hot gas engine construction employing either externalcombustion, internal combustion, or a combination of both internal andexterna1 combustion. The engine has a fresh air or gas intake meansconnected to a casing with a motor connected to the opposite end of thecasing, and a chamber in the casing having heat supplied thereto byeither heat exchangers or by internal ignition of combustionable fluidsthereby effecting the expansion of the gas and the increase of thepressure in the chamber between the intake means and the motor means.This forces the heated gases out of the chamber through the motoreffecting the driving of the motor which has its output connectedthrough suitable means to a load to be driven along with being drivinglyconnected to the intake means for effecting the operation of the same tointroduce fresh air or gas into the chamher; 1

12 Claims, 41 Drawing Figures nor GAS ENGHNE BACKGROUND OF THE INVENTIONPresent day engines are mainly of the internal combustion types such asthe Otto cycle, Diesel cycle, and the gas turbine.

The Otto and Diesel engines operate by compressing the fuel-air mixtureinside the engine cylinder, igniting the mixture, and deriving powerfrom the combusted mixture as it expands in the engine at greaterpressure. Of the shortcomings and disadvantages of this type of engine,there are five basic shortcomings most outstanding which cause loss ofenergy which would otherwise be available to the engine. Firstly, thepressures existing at combustion prevent high compression ratios whichwould otherwise be desirable in order to make use of the availableenergy lost due to the unused volume of air existing in the top of thecylinder. Secondly, the fuel-air mixture must burn rapidly, but notexplosively, so that the mixture begins burning before the pistonreaches the top of the cylinder and continues the burning process asthepiston starts downward in the cylinder. Thus, the fuel which burns priorto the piston reaching the top of its stroke in the cylinder actsagainst the force of the power stroke ofthe engine. Further, the fuelthat burns after the piston has initiated its downward strokecontributes only after it has burned so that full advantage of theburning and combustion process is not available to the piston. Thirdly,the com busted air is still expanding from the energy in it at thebottom of the power stroke with this energy of expansion being lost outthe engine exhaust with the requirement that a muffler or silencer mustbe provided due to the significance of the degree of energy being lost.Fourthly, the heat in the escaping exhaust gases cannot be directlyrecovered and incorporated directly in the Otto or Diesel cycles due tothe nature of their cycles. Fifthly, both the Otto and Diesel engines donot provide for complete combustion due to the restrictions of fuelburning time and the nature of fuel ignition in each type of engine.This results in the incomplete combustion products being discharged withthe exhaust gases thereby polluting the surrounding atmosphere not onlydue to the carbon monoxide produced by combustion and being discharged,but also due to the hydrocarbon pollutants being discharged due to theincomplete combustion process.

A major consideration in the design of combustion engines today isdirected at improving the combustion efficiency to reduce the amount ofpollutants discharged to the surrounding atmosphere while maintaining ahigh thermal efficiency of the engine. As is well known, because thecombustible charge in internal combustion engines is not alwayscompletely consumed during the ignition and combustion phase, theexhaust products discharged to the atmosphere from the engine containelements which contribute to the problem of air pollution. Some of theseproducts are considered a SUMMARY OF THE INVENTION Consequently, it isone of the principle objects of the present invention to provide a hotgas engine which overcomes these and other disadvantages.

The present invention provides the advantages of having a continuouscombustion process rather than combustion having to take place in timedcycles as in the Otto and Diesel engines. Further, the combustionchamber of the invention may be of any desired size and design whichfacilitates complete combustion of the fuel. A choice of any practicalfuel can be used in the engine thus substantially lowering operatingcosts. Further, engine efficiency is readily increased by recovering theheat of the exhaust gases and using the recovered heat to heat the airin the chamber. Still further, the gas in the chamber is permitted tofully expand before leaving the engine, this further increasing theefficiency of the engine while eliminating the need for power robbingmufflers.

The present invention has as one of its features the provision of beingselectively operable as a combined internal-external combustion enginewith the ability of also beingoperated as either one individually sothat a typical usage might be to discontinue the internal combustionphase of operation in areas where no pollutants whatsoever may bedischarged to the atmosphere so that the engine will continue operationcompletely in the external combustion phase with only a slight decreasein output as the loss of heat provided to the engine by the internalcombustion process can be somewhat compensated for by increasing theheat provided to the engine by the external combustion sources.

In those areas where an engine must continuously run under conditionsrequiring minimum or no pollutants discharged to the atmosphere, thepresent invention has the feature where it can be provided strictly asan external combustion engine where the external combustion takes placein conditions most favorable to complete combustion of the combustiblematerials with the discharge from such external combustion beingsubjected to treatment so that the final discharge contains nopollutants whatsoever while at the same time the heat supplied to theengine is uneffected by such treatment so that engine efficiency remainsthe same regardless of the treatment provided to the external combustiondischarge to remove pollutants therefrom.

When operating the present engine as an external combustion engine, thispermits combustion to take place in a carefully controlled environmentso that complete combustion is assured with no undesirable productsbeing discharged to contaminate the atmosphere, thus eliminating theproblem of unburnt contaminants in the exhaust products ejected from theengine as no combustion would take place within the engine itself.

In the internal combustion engine, where the fuel is burnt at hightemperature in explosive conditions, noxious pollutants are emitted. Bycomparison, the present engine, when operated as an external combustionengine, would produce virtually no pollutants, even when hydrocarbonfuel is being used for heating the cylinders, for external combustiontakes place in conditions which can be carefully controlled. Further, asthe engine can be driven by any heat source which may be readilyavailable, and as there are many other possible heat sources other thanhydrocarbon fuels, it is envisioned the development of special fuels foruse with the engine which would completely eliminate the problem ofpollutants emitted by engines to the surrounding atmosphere.

A feature of the present invention is that when operated as an internalcombustion engine either by itself or in combination with externalcombustion, the matter of unburnt combustion products is attended to bythe novel engine construction such that due to the design of thecombustion chamber and surrounding air-flow passages the combustion willbe substantially completed with substantially all the fuel contained inthe combustion chamber being burnt along with any contaminants thereinprior to the ejection of the exhaust gases to the surroundingatmosphere.

A further feature is the provision of an internal combustion chamberwhich provides an environment for efficient combustion of thecombustible charge so that fuel consumption will be improved assubstantially all the fuel will be consumed upon initial combustion,with the heat of combustion being maintained and combustion continued sothat contaminants in the exhaust are substantially minimized if notcompletely eliminated.

A further feature of this invention is its having a constant torque overa wide operating range which allows the engine to be used on widelyvarying loads with fewer torque conversion requirements than presentengines.

A further feature is the provision of an engine which can be startedwith a high torque from an initial stationary position and which can bedirectly connected to the load to be driven with the elimination of anyintermediate clutches, gear shifts, torque convertors, or any other ofthe heavy type of drive trains presently required when coupling anengine to the load to be driven.

A further feature is the provision of an engine structure in componentparts in which the respective portions forming the overall engine can bereadily removed as individual units for inspection, repair, andreplacement with a mimimum of time and equipment being required.

A further feature is the provision of an engine which can run on almostany type of fuel, has a mimimum of moving parts providing for anextended engine life, requires little maintenance, can be mounted andrun for indefinite periods in any engine position whatsoever, and ispractically free of noise.

Still a further feature of the invention is to provide an externalcombustion engine in a closed and sealed system where the system can beinitially pressurized and the operating gas selected thereby maximizingthe efficiency obtained by the engine for its selected purpose.

A further feature of the invention is a convenient compressed air sourceby means of a connection to the chamber.

Further features of the invention are directed to improvements whichrepresent improved operating and wear characteristics, simplicity ofmanufacture, elimination and/or reduction in problems of alignment ofparts, minimization of moving parts, and engine parts which are readilyinterchangeable so that only a minimum of parts need be maintained onhand for servicing and repair of the engines when required.

As the present engine will largely eliminate noise, will minimize theproduction of noxious pollutants discharged to the surroundingatmosphere, is capable of being run on various types of fuel or othersources of heat, and has few moving parts so that maintenance of theengine is greatly minimized, it is apparent that this is an engine whichcan be of exceptional benefit to the public as an inexpensive, reliableand generally pollution free engine.

The engine of the present invention generally comprises a casing havinga chamber therein with heat exchangers of an external-combustion sourceor an internal-combustion source or both being disposed in the chamber,a positive displacement compressor connected to one end of the casingand opening into the chamber for supplying air or gas thereto, a motorconnected to the other end of the casing and in communication with thechamber in the casing such that the heated expanded gas from the chamberpasses through the motor and does work on the same by driving the motor,the output of the motor in turn being drivingly connected to the inputof the compressor to drive the compressor at a given ratio such that themotor is always turning at a greater speed than the speed of thecompressor or should the compressor and motor be of different designs,then the motor is always turning with a greater volume flow through itthan the compressor. Thus, the air or gas is heated within the chamberthereby causing a pressure buildup in the chamber and forcing the hotair to flow out the motor driving the same which, in turn, through amechanical coupling with the compressor, drives the compressor in amanner to admit fresh air or gas into the chamber. The hotter the air isheated, the greater the expansion and pressure differential, and thegreater the torque of the motor which results in greater efficiency ofthe engine.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show for thepurpose of exemplification, without limiting the invention or claimsthereto, certain practical embodiments illustrating the principals ofthis invention wherein:

FIG. 1 is a diagrammatic view of an embodiment of the present inventionillustrating an internal-external combustion engine;

FIG. 2 is a diagrammatic view of another embodiment of the presentinvention illustrating an external combustion engine connected foroperation in a sealed closed-loop system;

FIG. 3 is a diagrammatic view of another embodiment of the presentinvention illustrating an internalexternal combustion engine similar tothe engine of FIG. 1 but utilizing a compressor and motor of thereciprocating type; and

FIG. 4 is a diagrammatic view of a further embodiment of the presentinvention illustrating an external combustion engine similar to FIG. 2but having a pressure recovery system and utilizing a three-lobe rotortype compressor and motor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, wherein forthe purpose of illustration is shown preferred embodiments of theinvention, and referring to FIG. 1, there is indicated generally anengine 11 which comprises a positive displacement compressor 12 and amotor 13 interconnected by a casing 14 containing a chamber 15 incommunication with the compressor and motor.

The compressor 12 is of the positive displacement rotary type comprisinga housing 16 having an inlet port 17 and an oulet port 18 with two-loberotors 19 and 20 rotatively mounted on shafts 21 and 22 for rotation inopposed directions as indicated by the arrows 23 and 24. The outerperipheral portions 25 and 26 of the twolobe rotors 19, 20 are disposedin sealing engagement with the inner peripheral surface 27 of thecompressor housing 16, and rotate in a manner as to always maintainperipheral contact with each other and with the peripheral inner surface27 of the compressor housing 16 so that there is always a continuousseal between the inlet port 17 and outlet port 18 with fresh airentering the inlet port, being compressed, and discharged through theoutlet port to the chamber 15. Working chambers 31 are defined betweenthe rotor peripheral surfaces 25, 26 and the interior surface 27 of thecompressor housing 16. It will be apparent therefore that, as the rotorsrotate relative to one another and relative to the housing 16, theworking chambers 31 will transfer air from the volume adjacent to theinlet port 17 to the outlet port 18 where the compressed volume wouldthen be discharged to the chamber 15. a

The motor 13 is identical to the compressor 12, with like referencenumerals being utilized to indicate like parts 16 to 27 respectively.However, it should be understood that the invention is not limited tothe specific embodiment shown having two rotary rotors of the two-lobetype as other combinations may be used, such as the type usingthree-lobe rotors, sliding vane, or helical lobe.

The compressor outlet port 18 is connected to the casing 14 and opensinto chamber in the casing. The inlet opening 17 of the motor 13 isconnected to the opposite end of the casing 14 and opens into chamber 15in the casing. The chamber 15 is divided into a series of interconnectedchambers and passages 32 to 37 forming a tortuous path along which theair flow is directed through chamber 15. Disposed in chamber 32 are heatexchanger coils 41 along with the coils 42 of a recovery heat exchanger.Heat exchanger 41 is connected to an external heat source (not shown)with heat exchanger 42 being connected to coils 43 disposed in outletport 16 of the motor 13. Disposed in chamber 37 are the coils of asecond heat exchanger 44 and a third heat exchanger 45. Heat exchanger44 is connected to an external heat source (not shown) with heatexchanger 45 being connected to an external combustion chamber 46 inwhich combustion takes part outside the environment of the engine butwith the heat from the combustion chamber being available to the airflowing thereover passing through chamber 37.

The chamber 35 also forms the internal combustion chamber with referencenumeral 54 designating an assembly consisting of a fuel injection jetand igniter with the fuel directed to the same first passing throughfuel heating coils 47 disposed in the juncture between chambers 35 and36 to preheat the fuel prior to ignition.

The rotors l9',20' of the motor 13 are connected to a load to be drivenby the engine along with also being connected by suitable mechanicalmeans (not shown) to the input shafts 21, 22 of the compressor 12 so asto drive the compressor rotors 19, in a predetermined ratio relative tothe rate of rotation of the rotors 19, 20' of the motor. Theratio ofrotation of therotors 19', 20 of the motor 13 to the rotors 19, 20 ofthe compressor ranges from a minimum ratio where the volume of airthrough the motor is slightly greater than the volume of air through thecompressor, up to a maximum ratio where, for the particular temperaturesand pressures in the engine, the mechanical advantage of the motor wouldno longer provide the work required to drive both the load and thecompressor. The maximum ratio limit is a design criterion which willvary depending on the efficiency of the compressor and motor, therequirements of the load to be driven, the maximum temperature in thechamber 15, etc.

The rotors 19, 20 and 19', 20 are disposed in their respective housings16, 16 and rotate in a manner as to always maintain peripheral contactwith each other and with their respective interior surfaces 27, 27' oftheir respective housings so that the chamber 15 in'the casing 14 isalways maintained closed from the intake port 17 of the compressors l2and the outlet port 18' of the motor 13.

In operation, starting from zero rotation of the motor 13 and compressor12 with chamber 15 initially unheated and the air contained thereinbeing at the same temperature as the air outside the engine 11, the airwithin the chamber 15 is initially heated by introducing heat therein byheat exchangers 44 and 45 along with initiating the internal combustionprocess in chamber 35. This heating process rapidly heats the air in thechamber 15 causing an expansion of the same and a pressure buildup inthe chambers 32 to 37, this pressure buildup forcing the expanded air toflow out of the chamber 15 and impinge against the rotors 19, 26' of themotor 13 effecting the rotation of the same which, in turn, through themechanical coupling with the compressor 12, effects the rotation of thecompressor rotors 19, 20 in a direction to admit fresh compressed air tothe chamber 15.

The fresh air enters the inlet port 17 of the compressor 12 and flowsinto chamber 31 where it is then trapped between the interior surface 27of the compressor housing 16 and the peripheral surfaces 25, 26 of therotors 19, 20 as the rotors 19, 211 turn and seal off the intake port17. The air is then discharged from the compressor 12 through outletport 18 into chamber 32 where it comes in contact with heat exchangers41 and 42 which begin the heating and expansion of the air. The heatedair then flows in a stream through passages 33 and 34 after which it isintroduced to the combustion chamber 35 where it is further heated bythe internal combustion process taking place at assembly 54. Thisfurther heated air then flows out of combustion chamber 35, throughpassages 36, and into chamber 37 where it is further heated by heatexchangers 44 and 45 and the walls of the external combustion chamber 46which further heats and causes further expansion of the air. In flowingfrom chamber 35 to passage 36, the heated air passes over and aroundfuel heating coils 47 to preheat the fuel prior to its being ignited atassembly 54.

From chamber 37, the expanded heated air flows out of chamber 15 intoinlet port 17' of the motor 13 where the air impinges upon the motorrotors 19, 20 effecting the rotation of the same, after which the air isdischarged from the motor through outlet port 16' passing over heatexchanger coils 43 prior to the discharge of the air from the engine1 1. Coils 43 recover some of the heat from the discharged air which isthen delivered to heat exchanger coils 42 disposed in chamber 32 for usein heating fresh air when introduced to chamber 15. Coils 53 thusrecover heat which would otherwise be lost to the surroundingatmosphere.

The hotter the air is heated in chamber 15, this being controlled by theamount of heat introduced by the heat exchangers and internal combustionprocess, the greater the expansion of the air therein, the greater thepressure differential created in the chamber, and thus the greater thespeed of the motor 13.

Should internal combustion not be wished, then the control of fuel toassembly 54 is cut-off by suitable means (not shown) so that the enginewould then oper' ate as an external combustion engine, the difference inheating being only that chamber 35 would not be utilized for combustionpurposes but merely as a passage to direct the heated air to which heatwould be provided by heat exchangers 41, 42, 44 and 45 by external heatsources. It is possible for the engine to maintain the same power outputby increasing the heat supplied to the engine by the heat exchangerswhen discontinuing the internal combustion process so that approximatelythe same amount of air expansion would take place in the chamber 15.

The air stream through the various chambers and passages 32 to 37 issuch that the air is continually heated and further expanded as itprogresses through the tortuous path with the coolest air flowing in theoutermost passages 33 thereby providing an insulating blanketimmediately inside the casing 14 thus preventing excessive loss of heatfrom the engine while minimizing any cooling or insulation requiredexternally of the engine.

In order to increase the power output of the motor, there is provided asuper charger compressor 51 which is of the same design as thecompressor 12 and motor 13 so that reference numerals 17" to 27" areutilized to identify like parts of the super charger. The volume ofairpassing through the super charger 51 exceeds the volume of air throughthe compressor 12 and is mechanically coupled by suitable means (notshown) to the compressor for driving by the same. The super charger 51enhances the degree of combustion of fuel at the assembly 54 in theinternal combustion chamber 35 by raising the air density inside theengine 11, this also serving to increase the power output from the motor13. The super charger increases the engine compression ratio therebyobtaining a more compact and powerful engine.

Cooling coils 52 may be provided between the outlet port 18" of thesuper charger and the inlet port 17 of the compressor in order to coolthe air heated by the compression process in the super charger prior tothe introduction of the air to the compressor, this serving to reducethe power consumed by the super charger.

Referring to FIG. 2 there is disclosed another embodiment of the presentinvention where reference numeral 61 designates an engine similar toengine 11 but being completely of the external-combustion type ratherthan of the internal-external combustion type. Parts shared between thisengine 61 and engine 11 of FIG. 1 are the compressor 12 and the motor13, with like reference numerals being used to designate like partsthroughout. A casing 14' having a chamber 63 therein is connectedbetween the compressor 12 and motor 13 with one end of chamber 63 beingin communication with outlet port 18 of the compressor, and the otherend of chamber 63 being in communication with inlet port 17 of the motor13. The chamber 63 is divided into passages 64, 65, and 66 so that gasentering the chamber 63 first flows in a stream along passage 64disposed adjacent the interior wall surfaces of the casing 14', the gasstream then being reversed and di rected through passage 65, after whichthe gas stream is again reversed and flows through passage 66 into motor13. An external combustion chamber 68 is located in chamber 63 at theend of passage 66 nearest the motor 13 and is connected to' heatexchanger coils 69 initially disposed along the length of passage 66 andextending therefrom by coils 70 along the length of passage 65. Theexternal combustion chamber 68 is connected to an external heat source(not shown) for providing heat to the same. The combustion chamber 68and coils 69 and 70 are disposed in the passages 65 and 66 in a mannersuch that the maximum heat is available at the combustion chamber 68with the heat diminishing as it progresses further away from thecombustion chamber along the passage 66 through coils 69, with the heatdiminishing still further as it passes back along the passages 65through coils 70 which terminate approximately at the entrance topassage 65. Thus, the coolest gas enters chamber 63 and flows throughpassage 64 effecting the cool gas blanket between the interior of theengine and the interior surface of the casing 14 minimizing theinsulation required for the same, after which the gas streams throughpassage 65 contacting initially the coolest of the heat exchanger coils70, the gas being continually heated and expanding as it comes incontact with progressively hotter coils 70, after which the gas streamsthrough passage 66 being still further heated and expanded as itcontacts progressively hotter coils 69 until at last it streams aroundthe exterior of the external combustion chamber 68 receiving the maximumheat prior to the gas being discharged to motor inlet port 17 and intothe motor 13 where the expanded gas effects the rotation of the rotorsin the same manner as described above in reference to FIG. 1.

The outlet port 18' of the motor 13 is connected by passage 71 to theinlet port 17 of the compressor 12. Cooling coils 74 are disposed inpassage 71 for cooling the heated gas discharged from the motor prior tothe gas being admitted to the compressor 12.

By utilizing this sealed typeofclosed-loop engine system for externalcombustion engine 61, it is possible to pre-pressurize the gas used inthe system to obtain the maximum power therefrom, along with being ableto select the gas best suited for increasing engine efficiency. Anexample would be the use of helium as the working gas andpre-pressurizing the gas throughout the engine system to a value ofabout 10 atmospheres thus greatly increasing the power of the engine ashelium has a higher thermal conductivity than air, providing fast heatabsorption and loss.

A bypass valve 76 is interposed between chamber 63 and passage 71 topermit the engine to have a braking effect on the driven load. Openingthe bypass valve 76 will shunt air from chamber 63 directly to passage71 thereby providing a braking torque effect on the motor 13 and theload driven thereby.

Similarly, referring to FIG' 1, a bypass valve 77 is utilized withengine 11 and is connected to chamber 15 at one end with the oppositeend being open to the ambient atmosphere so that by opening the bypassvalve air will be shunted from chamber 15 to the atmosphere therebyproviding a braking torque on the motor 13 and the load driven thereby.

Referring to FIG. 3, there isdisclosed a further embodiment of thepresent invention where reference numeral 81 designates aninternal-external combustion engine comprising a compressor 82 and amotor 83 interconnected by a casing 84 having a chamber 85 therein. Thecompressor 82 includes a cylinder 86 having an inlet port 87 and adischarge port 88 with a reciprocating piston 89 disposed in thecylinder and connected by a piston rod 90 to a crank shaft 91 whichrotates about the shaft 92 in the direction shown by the arrow 93. Aninlet passage 94 connects the inlet port 87 to the surroundingatmosphere, with a discharge passage 95 connecting the discharge port 88to the chamber 85. Associated with the inlet port 87 is an inlet valveassembly 96, and associated with the discharge port 88 is a dischargevalve assembly 97. Intake valve 96 controls the air flow from the intakepassage 94 to chamber 100 which is defined between the top surface ofthe piston 89 and the interior surfaces of the cylinder 86. Thedischarge valve 97 controls the discharge of the air from chamber 100 tothe discharge passage 95.

Motor 83 is identical to the compressor 82 so that reference numerals86' to 100' designate like or similar parts.

Chamber 85 in casing 83 is divided into a series of interconnectedchambers and passages 102 to 107 for directing the stream of air flowtherethrough. Disposed in chamber 102 are the coils of a first heatexchanger 111 connected to an external heat source (not shown). Disposedin chamber 107 are the coils 112 of a second heat exchanger which isalso connected to an external combustion chamber 114. Chamber 105comprises an internal combustion chamber having an assembly 113 forinjecting and igniting the fuel provided thereto by fuel line 1141, thefuel passing first through fuel heating coils 115 disposed betweenchambers 105 and passage 106 for preheating the fuel prior to itscombustion at assembly 113.

The output shaft 92 of the motor is connected both to a load to bedriven by the engine as well as being connected by suitable means (notshown) to drive the shaft 92 of the compressor 82 such that thecompressor and motor turn in a given ratio with the motor always turningat a speed such that the volume of air passing therethrough is greaterthan that passing through the compressor.

The valves 96, 97 and 96, 97' open and close their respective ports intimed relationship to the movement of their respective pistons 89, 89 byany one of several means suitable for this purpose as known in thisfield of art.

In operation, starting from zero rotation, air is initially heatedwithin the chambers and passages 102 to 107 by heat exchanger coils 111and 112 as well as by the internal combustion process taking place inchamber 105. This heating process rapidly causes an expansion of the airwithin the chambers and passages thus effecting a pressure builduptherein, this pressure buildup forcing the heated expanded air to flowout of the chamber 85 and into the inlet passage 94 of the motor 83where it is directed into the motor chamber 108' impinging on the piston89' effecting the downward movement of the same. This causes therotation of shaft 92' which, in turn, through the mechanical couplingwith the compressor 82, effects the rotation of compressor shaft 92 in amanner to introduce fresh air into the chamber 85.

Considering a conventional cycle of the compressor 82, we start with thepiston at its maximum upward position in the cylinder 86 with both inletport 87 and outlet port 88 closed by their respective valves 96 and 97.The piston begins its downward movement in the cylinder andsimultaneously therewith inlet port 87 is opened by valve 96 to admitfresh air into chamber 100. When the piston reaches its lowest positionin the cylinder so that chamber 108 contains the maximum volume of air,the inlet port 83 is closed so that as the piston moves upwardly in thecylinder it compresses the volume of air in chamber 100 to the desiredcompression value. When the desired degree of compression is reached,the discharge port 88 is opened by valve 97 to permit the discharge ofthe compressed air from chamber 100 through discharge passage intochamber 85. This discharge continues as the piston continues its upwardmovement until the piston reaches its maximum upward position in thecylinder, at which time the discharge .port 88 is closed, therebycompleting a cycle of operation for the compressor, after which theinlet port 87 is open to initiate a new cycle of operation.

Considering a conventional cycle of the motor 83, and starting with thepiston 89' in its maximum upward position with both inlet port 87 anddischarge port 88' being closed to chamber inlet port 87 is initiallyopened admitting hot expanded gases to chamber 100 which impinge on thepiston 89 driving the same in a downward direction in the cylinder 86'.Approximately halfway between the top and bottom position of the pistonin the cylinder, the intake port 87' is closed to chamber 180' and theair trapped in chamber 180' is permitted to pass through a phase ofadiabatic expansion thereby driving the piston to its lower mostposition in the cylinder. At this point the discharge port 88' is openedto the chamber 100' by valve 97' so that as the pistonmoves upwardly inthe cylinder the air in chamber 100 is discharged through dischargepassage 95' to the atmosphere. Upon the piston reaching its maximumupward position, the discharge port 88 is closed to chamber 100' and thecycle of operation of the motor is completed. Upon the opening of theinlet port 87' to chamber 100', a new cycle of operation is initiated.

While the speed of the engine is readily controlled by controlling theheat of the air in the chamber 85, a further engine speed control may beprovided in the form of a butterfly-type valve 113 disposed in thepassage 114 connecting the compressor inlet passage 941 to theatmosphere so as to control the volume of air flow into the compressor.Further, the engine speed could also be controlled by controlling therate of fuel being utilized for the internal combustion in chamber atassembly 1113'.

Referring now toFiG. 4 there is disclosed a further embodiment of thepresent invention wherein the reference numeral 121 generallyindicatesan external combustion engine which comprises a positive displacementcompressor 122 and a motor 123 interconnected by a casing 1241 having achamber 125 therein.

The compressor 122 is of the three lobe rotary type and comprises ahousing 126 having an inlet port 127 and an outlet port 128 withthree-lobe rotors 127 and 128 which are rotatively mounted on shafts 129and 130 for rotation in opposed directions as indicated by the arrows131 and 132 respectively. The outer peripheral portions of each rotor127, 128 is disposed in continuous sealing engagement with the innersurface 133 of the compressor housing 122. The outer peripheral surfacesof the rotors are in continuous rotative sealing engagement with theadjacent portions of each other so that at all times, including duringrotation, the inlet port 127 is sealed from the outlet port 128. Aseries of working chambers 135 are defined between the outer peripheralsurfaces of the rotors 127, 128 and the interior surface 133 of thecompressor housing. It will be apparent that, as the rotors rotaterelative to one another and relative to the housing 122, the workingchambers 135 between the peripheral surfaces of the rotors 127 and 128and the adjacent portions of the interior housing surface 133 willtransport working gas from inlet port 127 to outlet port 128 to bedischarged to chamber 142.

The motor 123 is substantially identical to the compressor 122 so thatlike reference numerals have been utilized to designate like parts 123through 135 respectively.

The compressor outlet port 128 is connected to one end of the chamber125, with the inlet port 127 of the motor 123 being connected to theopposite end of the chamber 125. The chamber 125 is divided into aplurality of interconnected chambers and passages 141 to 144 forming atortuous path for the gas flow through the chamber.

Disposed along chamber 144 and extending along chamber 141 are heatexchanger coils 145 receiving heat from an external heat source (notshown) or from an external combustion chamber 146 which may be disposedin chamber 144. The outlet port 128' of motor 123 is connected to theinlet port 127 of the compressor 122 by means of passages 151, heatexchange coils 152 disposed in passages 143, heat exchange coils 153disposed in passages 142, passage 154, air cooled heat exchange coils155, and passage 156 which connects to compressor inlet port 127. Inthis manner the hot gas which is discharged from the motor 123 isdirected through heat exchange coils 152 and 153 into the chamber 125for use in heating the gas in the chamber, after which the gas stream isdirected by passage 154 to a heat exchanger which cools the gas back tothe desired temperature prior to the gas being recycled through passage156 back into the compressor 122 for cycling again through the engine.

To assist in compressing the gas in the compressor 122, and forrecovering a portion of the energy of the compressed gas which wouldotherwise be discharged from the motor and wasted due to incompleteadiabatic expansion in the motor 123, there are provided ports 161 inthe compressor 122 interconnected by a passage 162, along with ports161' in the motor interconnected by a passage 162', with passages 162and 162' being interconnected by means of a pressure holding tank 163.In this manner the pressure is equalized between the chambers 135 and135' as these chambers are moved by the rotors so as to momentarily comein contact with the ports 161, 161'. In this manner the increasedpressure at the motor 123 is discharged through the passages 162, 162'and assists the compressor in compressing the air in chambers 135.

In operation, the gas in chamber is heated by coils 145 causing theexpansion of the gas and the increase of pressure of the same, theheated expanded gas acting on the motor rotors 127', 128 effecting therotation of the same and their respective shafts 129, 130'. The motorshafts are connected to a motor output (not shown) which is connected tothe load to be dirven (not shown) as well as being mechanicallyconnected by suitable means to the compressor shafts 129, 130 so thatthe motor and compressor rotors always turn in a given ratio with themotor always turning at a speed such that the volume of gas passingtherethrough is greater than that passing through the compressor.

As the motor turns, the compressor rotors turn thus discharging freshcompressed gas through outlet port 128 into the chamber 125. The gasstream first contacts heating coils 145, after which the air flowstreams along interconnected passages 142 and 143 contacting coils 153and 152 respectively which further heat and expand the gas, with the airstream then flowing through chamber 144 and passing over coils 145 andcombustion chamber 146 still further heating and expanding the gas priorto its discharge from chamber 125 into motor inlet port 127. The motorrotors 127, 128' are driven by the hot gases acting thereon, after whichthe gases are discharged through discharge outlet 128 and pass throughpassage 151 to be directed into heating coils 152, 153 for recovery ofthe heat in the discharged gases for utilization in heating the air inthe chamber 125, after which the air flows through passage 154 tocooling coils 155 where the gas is cooled to the desired temperatureprior to its being reintroduced to the compressor by passage 156connected to compressor inlet port 127. In addition, a portion of theheated compressed gas flows through ports 161 to be discharged into thecompressor housing at ports 161 for assisting in compressing the air inthe compressor 122 prior to discharge of the compressed fresh air intothe chamber 125.

As in the other embodiments, it is to be noted that the air streamthrough the chamber 125 is arranged such that the air is continuallyheated and further expanded as it progresses through the tortuous pathof the chambers 141 through 144, with the coolest air flowing in theoutermost passages 142 thereby providing a cool air insulating blanketadjacent the interior of the casing 124 to prevent excessive loss ofheat from the engine while minimizing the cooling or insulation requiredexternally of the engine casing.

As previously discussed, by utilizing a closed-loop system for anexternal-combustion engine it is possible to maximize the efficiency ofthe engine by prepressurizing the gas used in the system along with theselecting of the gas best suited for the working temperatures andpressures involved. An example would be the use of helium as the workinggas and prepressurizing the closed-loop system to a value of about 10atmospheres which would greatly increase the efficiency of the engine.

It is to be understood that the form of this invention herewith shownand described is to be taken as a preferred example of the same, andthat various changes in the shape, size, and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subjoined claims.

What 1 claim is:

1. A hot gas engine comprising: a casing having a chamber therein;heating means disposed in said chamber for supplying heat thereto;intake means connected to said casing for supplying a gas to saidchamber and including a housing having an inlet port and an outletport,said outlet port being in communication with said chamber forintroducing gas therein; 1 motor means connected to said casing forreceiving gas from said chamber and including a housing having an inletport and an outlet port, said inlet port being in communication withsaid chamber for receiving gas therefrom, said gas performing work onsaid motor means by driving the same, after which said gas is dischargedfrom said motor means through said outlet port; said chamber beingcontinuously closed off from said intake means inlet port and said motoroutlet port; said motor means drivingly connected to said intake meansfor driving the same at a selectable ratio relative to the speed of saidmotor means, said ratio being selected so that the volume of gas passingthrough the motor means is greater than the volume of gas passingthrough the intake means; means interconnecting a gas compression stageprovided in said intake means housing with a gas expansion stageprovided in said motor means housing for equalizing the pressure of thegas passing through said interconnected compression and expansionstages; whereby said heating means heats the gas in said chamber betweenthe intake means and motor means effecting the expansion thereof with anassociated increased pressure buildup in said chamber, this pressureincrease forcing the gas out of said chamber to perform work on saidmotor means, said motor means in turn driving said intake means to admitfresh gas to said chamber. 2. The hot gas engine as set forth in claimll further characterized by:

said intake means inlet port being in communication with said motormeans outlet port so as to form a closed loop system for directing thegas flow therebetween; and cooling means disposed between said intakemeans inlet port and said motor means outlet port for cooling the hotexhaust gas discharged from said motor means prior to said gas beingintroduced into said intake means. 3. The hot gas engine as set forth inclaim ll further characterized by:

a combustion chamber formed in a portion of said chamber; acombustionable working fluid introduced into said combustion chamber;and ignition means associated with said combustion chamber forinitiating combustion of the working fluid thereby introducing heatintosaid chamber. 4. The hot gas engine as set forth in claim 1 furthercharacterized by:

said chamber being divided into first and second gas flow passagewaysfor directing the flow of gas through the engine, said first passagewaydirecting the fresh gas introduced by said intake means along theinterior surfaces of said chamber thereby generally forming aninsulation blanket of cool gas immediately adjacent said interiorchamber surfaces, said second passageway receiving the gas from saidfirst passageway and directing it over a tortuous path through theremainder of said chamber; and 5 said heating means comprising a heatexchanger including heat exchanging coils disposed along said secondpassageway with the coolest coil being disposed nearest the end of saidsecond passageway adjoining said first passageway and the hottest coil lbeing disposed nearest the opposite terminal end of said secondpassageway so that gas introduced from said first passageway initiallycontacts the coolest heat exchange coil with the gas expanding l andabsorbing heat from continually hotter coils as the gas progressivelyflows through said second passageway over said coils until the dischargeof the gas from said chamber to said motor means.

5. The hot gas engine as set forth in claim 1 further characterized bysaid intake means comprising:

' a cylinder having an inlet valve and an outlet valve;

a piston disposed for reciprocating movement in said cylinder;

a variablevolume working chamber defined in said cylinder between saidvalves and said piston;

a drive shaft eccentrically connected to said piston so that rotation ofsaid drive shaft effects the reciprocation of said piston; and

means associated with said drive shaft to sequentially operate saidvalves;

whereby gas is introduced to said working chamber,

compressed therein by said piston, and the compressed gas is exhaustedtherefrom through said outlet valve in communication with said chamber.

6. The hot gas engine as set forth in claim 1 further characterized bysaid motor means comprising:

a cylinder having an inlet valve and an outlet valve;

a piston disposed for reciprocating movement in said cylinder;

a variable volume working chamber defined in said cylinder between saidvalves and said piston;

a driven shaft eccentrically connected to said piston so thatreciprocation of said piston effects the rotation of said drive shaft;and

means associated with said driven shaft to sequentially operate saidvalves;

whereby the heated gas is received in said working chamber from saidchamber, expands and cools in said working chamber performing work onsaid piston, after which the gas is discharged from the working chamberthrough said outlet valve.

7. The hot gas engine as set forth in claim 1 further characterized by:

a gas flow control means associated with said intake means inlet portfor controlling the volume and flow of gas introduced to said intakemeans through said outlet port.

8. The hot gas engine as set forth in claim it further characterized by:

bypass means operable to provide communication between said chamber andthe ambient atmosphere so that operating said bypass means shunts gasfrom said chamber to the atmosphere to relieve the heat and pressure insaid chamber thereby providing a breakingtorque effect on said motormeans.

9. The hot gas engine as set forth in claim 1 further characterized by:

inlet port and an outlet port, said inlet port receiving fresh gas, saidoutlet port in communication with said intake means inlet port, wherebyfresh gas is initially compressed by said auxiliary intake means therebyincreasing the volume and density of the gas introduced to said intakemeans and eventually to said chamber so as to increase the compressionratio of the engine.

12. The hot gas engine as set forth in claim 1 wherein said meansinterconnecting the gas compression stage and the gas expansion stagecomprises a conduit directly interconnecting said stages.

1. A hot gas engine comprising: a casing having a chamber therein;heating means disposed in said chamber for supplying heat thereto;intake means connected to said casing for supplying a gas to saidchamber and including a housing having an inlet port and an outlet port,said outlet port being in communication with said chamber forintroducing gas therein; motor means connected to said casing forreceiving gas from said chamber and including a housing having an inletport and an outlet port, said inlet port being in communication withsaid chamber for receiving gas therefrom, said gas performing work onsaid motor means by driving the same, after which said gas is dischargedfrom said motor means through said outlet port; said chamber beingcontinuously closed off from said intake means inlet port and said motoroutlet port; said motor means drivingly connected to said intake meansfor driving the same at a selectable ratio relative to the speed of saidmotor means, said ratio being selected so that the volume of gas passingthrough the motor means is greater than the volume of gas passingthrough the intake means; means interconnecting a gas compression stageprovided in said intake means housing with a gas expansion stageprovided in said motor means housing for equalizing the pressure of thegas passing through said interconnected compression and expansionstages; whereby said heating means heats the gas in said chamber betweenthe intake means and motor means effecting the expansion thereof with anassociated increased pressure buildup in said chamber, this pressureincrease forcing the gas out of said chamber to perform work on saidmotor means, said motor means in turn driving said intake means to admitfreSh gas to said chamber.
 2. The hot gas engine as set forth in claim 1further characterized by: said intake means inlet port being incommunication with said motor means outlet port so as to form a closedloop system for directing the gas flow therebetween; and cooling meansdisposed between said intake means inlet port and said motor meansoutlet port for cooling the hot exhaust gas discharged from said motormeans prior to said gas being introduced into said intake means.
 3. Thehot gas engine as set forth in claim 1 further characterized by: acombustion chamber formed in a portion of said chamber; a combustionableworking fluid introduced into said combustion chamber; and ignitionmeans associated with said combustion chamber for initiating combustionof the working fluid thereby introducing heat into said chamber.
 4. Thehot gas engine as set forth in claim 1 further characterized by: saidchamber being divided into first and second gas flow passageways fordirecting the flow of gas through the engine, said first passagewaydirecting the fresh gas introduced by said intake means along theinterior surfaces of said chamber thereby generally forming aninsulation blanket of cool gas immediately adjacent said interiorchamber surfaces, said second passageway receiving the gas from saidfirst passageway and directing it over a tortuous path through theremainder of said chamber; and said heating means comprising a heatexchanger including heat exchanging coils disposed along said secondpassageway with the coolest coil being disposed nearest the end of saidsecond passageway adjoining said first passageway and the hottest coilbeing disposed nearest the opposite terminal end of said secondpassageway so that gas introduced from said first passageway initiallycontacts the coolest heat exchange coil with the gas expanding andabsorbing heat from continually hotter coils as the gas progressivelyflows through said second passageway over said coils until the dischargeof the gas from said chamber to said motor means.
 5. The hot gas engineas set forth in claim 1 further characterized by said intake meanscomprising: a cylinder having an inlet valve and an outlet valve; apiston disposed for reciprocating movement in said cylinder; a variablevolume working chamber defined in said cylinder between said valves andsaid piston; a drive shaft eccentrically connected to said piston sothat rotation of said drive shaft effects the reciprocation of saidpiston; and means associated with said drive shaft to sequentiallyoperate said valves; whereby gas is introduced to said working chamber,compressed therein by said piston, and the compressed gas is exhaustedtherefrom through said outlet valve in communication with said chamber.6. The hot gas engine as set forth in claim 1 further characterized bysaid motor means comprising: a cylinder having an inlet valve and anoutlet valve; a piston disposed for reciprocating movement in saidcylinder; a variable volume working chamber defined in said cylinderbetween said valves and said piston; a driven shaft eccentricallyconnected to said piston so that reciprocation of said piston effectsthe rotation of said drive shaft; and means associated with said drivenshaft to sequentially operate said valves; whereby the heated gas isreceived in said working chamber from said chamber, expands and cools insaid working chamber performing work on said piston, after which the gasis discharged from the working chamber through said outlet valve.
 7. Thehot gas engine as set forth in claim 1 further characterized by: a gasflow control means associated with said intake means inlet port forcontrolling the volume and flow of gas introduced to said intake meansthrough said outlet port.
 8. The hot gas engine as set forth in claim 1further characterized by: bypass means operable to provide communicationbetween said chambEr and the ambient atmosphere so that operating saidbypass means shunts gas from said chamber to the atmosphere to relievethe heat and pressure in said chamber thereby providing a breakingtorque effect on said motor means.
 9. The hot gas engine as set forth inclaim 1 further characterized by: heat exchange means associated withsaid chamber and said motor means outlet port and disposed inheat-exchanging relationship with the hot exhaust gas discharged throughsaid motor outlet port for abstracting heat therefrom and introducingsaid abstracted heat into said chamber.
 10. The hot gas engine as setforth in claim 2 further characterized by: said gas in said closed loopsystem being pre-pressurized to a selected value above ambientatmospheric pressure.
 11. The hot gas engine as set forth in claim 1further characterized by: auxiliary intake means including a housinghaving an inlet port and an outlet port, said inlet port receiving freshgas, said outlet port in communication with said intake means inletport, whereby fresh gas is initially compressed by said auxiliary intakemeans thereby increasing the volume and density of the gas introduced tosaid intake means and eventually to said chamber so as to increase thecompression ratio of the engine.
 12. The hot gas engine as set forth inclaim 1 wherein said means interconnecting the gas compression stage andthe gas expansion stage comprises a conduit directly interconnectingsaid stages.